July 10 – Go Climb A Tree!

Today’s factismal: There are 411 different types of cell in a healthy adult human.

In science, the interesting questions are always the weirdest ones. They are interesting because (1) most people understand that importance of the question once they hear it and (2) few people would have any idea of how to answer the question. “How many different types of cell does a healthy adult human have?” is one of those questions. It is important because the different types of cells do different things in the body and knowing the relative number of different types of cell with similar characteristics can tell us much about that characteristic’s importance. For example, 145 of those 411 different types of cell are types of neuron; obviously, thought is an important part of the human biological makeup!

So the question is clearly important, but how do we answer it? How can we know how many different types of cell a healthy adult human has? Did they go out and pick apart a politician, putting each cell type into a different pile? Sadly, no (the politicians objected). Instead, the researchers used a technique known as cladistic analysis. They looked over different tissue samples from dozens of different donors and were able to identify features that each cell type had in common. For example, mitochondria were present in most cells so the list was divided into those cells with mitochondria and those without; it “branched” at that point. The cells without mitochondria can further be broken down into those without nuclei and those with.

A tree of life cladogram (Image courtesy American Museum of Natural History)

A tree of life cladogram
(Image courtesy American Museum of Natural History)

Because a written list of all of these differences would be very hard to read (and even harder to keep track of), most scientists instead draw it as a tree-like structure known to geeks as a cladogram (“branch drawing”). You are probably familiar with the “tree of life” which was made in the same way as the tree of human cells. Once the scientists run out of meaningful differences between the different branches, the cladogram in complete and you can find out how many different types of thing there are by simply counting the branches.

Even better, the relationships between the branches often tell us a lot about how things are related. On the tree of life, we know that mammal (like us) are more closely related to lizards (like politicians) than they are to green plants (like broccoli). Those relationships can then help us understand things like “will this heart medicine be dangerous for my kidneys?”

Of course, making these cladograms takes time and effort, but it can be fun. If you’d like to get in on the fun, the folks at Citizen Sort have developed a series of sorting games that you can do to actually sort out data that they will use to understand more about biology. To get in on the fun and games, head over to:

July 7 – What A Stench!

Today’s factismal: In 1855, Michael Faraday wrote a letter to the editor about pollution in the Thames River.

We often think of pollution as being a modern problem, but the truth is that the world is a lot cleaner now than it used to be. Though the Cuyahoga River did famously catch fire in 1969 (and at least a dozen times before that), it and other rivers in the USA have since been cleaned up and now support vibrant ecologies. Air pollution has decreased over the past three decades (with the notable exception of CO2), and ground water contamination is less common than ever.

But in the 1800s, things seemed to be headed the other way as the Thames River demonstrated. Thanks to a rapid increase in industrialization coupled with a laissez-faire approach to waste treatment (which at the time mostly meant “dump it in the river and hope it doesn’t float”), the amount of sewage in the Thames River had jumped sharply. In addition to the offal, blood, and manure being put into the river by meat packers, there was runoff of dyes containing lead and other heavy metals from the fabric makers, and (worst of all) the combined effluent from more than a million people who had toilets but no plumbing in their homes.

A political cartoon showing Faraday giving his card to the river Thames (Image courtesy Punch)

A political cartoon showing Faraday giving his card to the river Thames
(Image courtesy Punch)

In 1855, the well-respected researcher Michael Faraday wrote a letter to the Times about the state of the Thames. (It is almost a shame that he wrote only once; if he had written nine times more, then we could say that “Faraday wrote ten times to the Times about the Thames”.) And just three years later, a combination of a heat wave and drought would create what the British called with characteristic understatement “The Great Stink”. These events led to the development of a modern sewer system in London which then created a decrease in both the odor and (more importantly) the number of cholera deaths.

Of course, getting rid of pollution isn’t something that just happens. It takes a dedicated group willing to report on the water quality of their local stream, river, or wetland. If that sounds like something that you’d like to do, then why not join one of these programs?
Georgia Adopt-A-Stream
Klamath Riverkeeper
Loudoun Stream Monitoring
Missouri Stream Team Program
OPAL Water Survey (England)

July 6 – Oh Baby, Baby!

Today’s factismal: In 1847, a woman was ten times more likely to die of puperal fever if she gave birth in a hospital.

One of the great paradoxes of the 1800s was the deadliness of doctors. Though they were dedicated to healing the sick and helping the ill, there were some circumstances where they seemed to do more harm than good. One of the most notorious of these was childbirth. If a woman gave birth at a hospital, then there was as much as a 30% chance that she’d die of puperal fever; also known as “childbed fever”, it was an infection that typically led to a deadly buildup of toxins in the blood. But if a woman gave birth at home, then there was only about a 3% chance of puperal fever.

When ten times more patients die in the hospital than at home, you’d think that the doctors would sit up and take notice. And they did. Doctors dismissed the idea that they could be the cause (in the words of one expert, “Doctors are gentlemen, and gentlemen’s hands are clean”) and instead suggested that the problem was the proximity to other patients or the lack of fresh air or poor nutrition on the part of the women. It wasn’t until Ignaz Semmelweis compared the mortality rate for hospital wards with midwives to that for wards where doctors delivered babies that the doctors were pinpointed as the cause. Because germs hadn’t been discovered yet, all Semmelweis could do is suggest that “cadaverous particles” were being carried by doctors as they went from autopsies to birthing rooms (yes, things were a lot looser back then).

To prove his hypothesis, Semmelweis started requiring that doctors wash their hands in a chlorinated lime solution (roughly equivalent to a weak bleach) before attending a pregnant woman. Overnight, the incident rates for puperal fever dropped to the same levels seen when women gave birth at home. And for ten years, Semmelweis tried to convince other doctors to follow his lead.

Needless to say, the medical establishment didn’t appreciate the news that they were the cause. The local doctors arranged to have Semmelweis fired and convinced his wife to have him committed to an insane asylum. In an ironic twist of fate, he died of sepsis just two weeks after being admitted, probably due to a beating that the guards had given him. But within two decades Semmelweis would be vindicated. Pasteur would conclusively demonstrate that most diseases are caused by germs; much of his early work focused on puperal fever and relied on Semmelweis’ insights.

Of course, doctors are still trying to learn more about diseases today. And they have learned from past experience and have somewhat more open minds than they did in the 1850s. What that means is that they are now asking for insights from people like you. At the Health Tracking Network, they’d like you to tell them about any symptoms you have (or don’t) relating to colds, the flu, or the stomach flu. Even better, you’ll earn money for charity by participating, which makes this a win-win-win. To participate, head over to


July 5 – Mountains Out Of Molehills

Ever wonder what makes the Ring of Fire, the Ring of Fire? Mary, Peter, and Daniel did. Join them as they discover the answer in today’s Secret Science Society adventure!



Peter and Mary were not jealous of much, but they looked at the pictures from Daniel’s vacation to Colorado with envy. While they had stayed at home over spring break, Daniel’s family had gone to the mountains to ski. And the first day back at school, he showed pictures from the trip to Mary and Peter over lunch.

“I can’t believe that it is so snowy there!” Mary said.

“Yeah,” Peter added. “And the mountains are so tall! Is it really a mile high there?”

“Yes, it is,” Daniel replied. “There’s even a step on the capitol building that tells you when you are a mile above sea level.”

“Cool! I wonder what made the mountains?” Mary asked.

“I don’t know, but I know who will,” Peter said.

“Mr. Medes!” all three chorused.

“Let’s go ask him!” Mary said.

The three friends cleared their lunch trays and then went down the hall to Mr. Medes’ classroom.

“Ah! A salubrious spring to you!” Mr. Medes greeted them. “What brings three such avid explorers to my room on a bright, sunny day?”

“We were looking at pictures of the mountains in Colorado,” Daniel said. “And we wondered what makes mountains.”

“That happens to be an excellent question!” Mr. Medes replied. “Would you believe me if I told you that grandparent’s didn’t know the answer but we do?”

As the three friends shook their heads, he went to the supplies cabinet and brought out two sheets of paper and a shaker of salt. He put the paper on the table, forming an “X”, and then spread a layer of salt about an inch thick over one side of the X.

“It is true,” Mr. Medes continued. “Until very recently, we thought that the surface of the Earth was just one big piece and stuck in one place. But then we discovered that it is broken into more than a dozen smaller pieces that move around very slowly. Those pieces are called”

“Plates!” Peter interrupted. “And they float on magma!”

“Well, you are right about them being called plates,” Mr. Medes replied. “But they don’t float on magma. Magma is molten rock and the outer part of the Earth is solid. But it oozes under pressure, sort of like bubble gum or fudge, which is why those plates can move around5r.”

“Oh. I guess the movies got that bit wrong,” Peter said, abashed.

“Movies usually do,” Mr. Medes smiled. “But as those plates glide along on the outer part of the Earth, which we call the mantle, they either move apart from each other, move beside each other, or run into each other. Now what I’ve done here is create a model that we can use to simulate how those plates move. Here’s how we’ll do the experiment. Daniel, you’ll hold the piece of paper that is on the top so that it cannot move. Mary, you’ll pull on the far side of the piece of paper that is underneath, so that it moves toward the other piece of paper. So those two pieces of paper are two plates moving on the outside of the Earth and that salt on top is like the crust of the Earth and will move with the plates. Got it?”

Seeing everyone nod, he continued. “Now what we have to do is to predict what will happen when the bottom plate runs into the top plate. Peter, what do you think will happen?”

“The sediment will stay in one place and slide off of the plate,” Peter replied.

“No,” Mary said. “You are wrong. The sediment will go under the top plate.”

“I don’t think that will happen,” Daniel said. “I think that the sediment will get scrunched up.”

Well, there’s only one way to find out,” Mr. Medes said. “Let’s move the plates!”

What do you think will happen? Do the experiment!


As Daniel held the paper on top still, Mary slowly pulled the bottom paper. As the far side of the “X” got longer, the other side got shorter, and the salt began to move together. At first, it didn’t look as if anything was happening. And then, as the three experimenters watched, the salt began to pile up and make hills and mountains.

“Wow!” Peter exclaimed. “The salt did pile up!”

“That’s right,” Mr. Medes said. “And that is the secret to orogeny, or mountain building. As the plates move together, the sediment gets squished up to form a great big mountain. Almost every large mountain chain was formed this way; the Himalayas, the Rockies, the Andes, the Alps all were made when one plate crashed into another.”

“And Hawai’i, too?” Mary asked.

“Actually, Hawai’i is a special case, just like Iceland and Yellowstone” Mr. Medes replied. “It was formed a different way, when a big blob of magma hit the bottom of the plate and melted its way through. And then there is the longest mountain chain in the world, the Mid-Atlantic ridge. It was formed when plates moved apart. But those are exceptions. The rule is that mountains are made when two plates crash together, just as most dents are made when two cars crash.”

“Gosh,” Daniel said. “So I was standing an old accident site!”

“Actually, the crash that made the Rocky mountains is still going on,” Mr. Medes replied. “The plates are still moving around. The Rockies were formed when the North American plate hit the Farallon plate. Normally, you’d get the mountains made very close to the coast, like the Cascades, the Aleutians and the Andes. But, because the Farallon plate went under the North American plate at such a shallow angle, it made the mountains very far inland.”

“Don’t the Cascade mountains and the Aleutians have lots of volcanoes?” Mary asked.

“Yes, they do!” Mr. Medes said. “And that is because of those plates. You remember how you predicted that the sediment would go down with the plate?”

“Yes,” Mary said. “I guess I was wrong.”

“Not entirely,” Mr. Medes replied. “Though most of the sediment stays up on the surface, some gets stuck on the plate and moves down into the mantle. And that sediment is chock full of water and limestone. When the sediment gets into the mantle, it releases that water and the carbon dioxide from the limestone. That gets into the surrounding mantle rocks and makes them melt, just a little. That new, hot magma goes up and erupts on the surface as a volcano. That’s why there are so many volcanoes around the Pacific rim and why we sometimes call it the ‘ring of fire’.”

At that moment the bell rang, signaling that it was time for class.

“Speaking of ringing,” Daniel said. “It is time for class. See you guys later!”

July 4 – A Blinding Flash!

Today’s factismal: There are 30 supernovae every second in the Universe but only eight of them have ever been close enough to see with the naked eye.

Almost a thousand years ago, astronomers across the world all saw something amazing: a bright, new star in the heavens. The new star was so bright that it could be seen in the daylight for 23 days and was clearly visible at night for nearly two years. It would take five hundred years before astronomers gave the phenomenon a name and another four hundred years before we understood that we had seen the death of a star in an explosion larger than any ever seen before; we had seen history’s first recorded supernova. Since then, we’ve seen eight more even though astronomers estimate that there are 30 new supernovae every second. The reason that we’ve seen so few is because space is so vastly, hugely, mindboggling big that, unless it is very close, even the brightest explosion is too dim to see without a very strong telescope.

The remains of the very first supernova ever recorded (Image courtesy NASA)

The remains of the very first supernova ever recorded
(Image courtesy NASA)

But that’s not the most amazing thing about the supernova of 1054. The most amazing thing is that the folks who wrote the most about it were also the people who developed fireworks. And the amazing thing about that is that the same physical processes that give fireworks their color is what tells us the composition of a star. For example, if you see a red firework, you know that they put strontium or lithium in the mix. A blue firework means copper. A bright yellow can only come form sodium in the mix. And adding calcium gives orange. So the color of the fireworks tell us what they are made of. Similarly, the color of a star tells us what chemicals are present in the star.

The color of each firework tells you what it is made of (My camera)

The color of each firework tells you what it is made of
(My camera)

What is cool about that is that the chemicals that are present in the star tell us a lot about when it formed. Because the heavier elements are formed in supernovae explosions, the first stars had nothing higher than helium in them; when they died, they added a little of the heavier elements to the universe, seeding space with the elements needed for the next generation of stars. Those had more of the lighter elements and very few of the heavier ones. When they became supernovae, they increased the amount of higher elements still further. So, by looking at the elements that are present in a star, we can tell about when it formed.

Naturally, that means that there is a citizen science opportunity. The folks at Stellar Classification Online Public Exploration (SCOPE) need your help in looking at the colors given off by stars. You’ll be able to determine the temperature and the composition of the stars using their handy-dandy online app; even better, because you’ll be comparing your star to one with a known composition and temperature, you won’t need to deal with any of the tedious details. So celebrate this Fourth of July by looking the biggest fireworks display ever!

July 3 – Cut The Mustard

Today’s Factismal: A single Garlic Mustard plant can make nearly 8,000 seeds.

If you had lived in Europe in the 1700s and wanted a little something spicy in your salad, you probably would have gone outside and grabbed some leaves off of a low rosette of greenery that your folks told you was called Jack-by-the-hedge. You could chop the garlicky leaves up in your salad, or mince them into a pesto, or grind the seeds into a mustard-like paste. If you had an ulcer or sore, you’d make a poultice of the leaves and use it as a bandaid. And if you had moved from Europe to America to find a better life (or hide from your creditors), then you might have brought a few seeds of this handy-dandy herb with you for your garden.

First year garlic mustard plants - yum! (Image courtesy New York Invasive Species Clearinghouse)

First year garlic mustard plants – yum!
(Image courtesy New York Invasive Species Clearinghouse)

A flowering garlic mustard plant (Image courtesy   Robert Vidéki)

A flowering garlic mustard plant
(Image courtesy
Robert Vidéki)

But what is handy-dandy in Europe can get out of control in North America, as anyone who has been harassed by a starling can attest. In Europe, the garlic mustard plant was an important part of the ecosystem, forming a habitat and food source for about 70 different species of insect. In North America, it is an invasive species that displaces native plants such as wild ginger and bloodroot. Those plants are the food source for many different species of butterfly, amphibian, and even deer; as a result, the invasion of garlic mustard can change a thriving ecosystem into a wasteland of nothing but garlic mustard.

Distribution of garlic mustard plants (Image courtesy USDA)

Distribution of garlic mustard plants
(Image courtesy USDA)

The threat posed by this invasive is spreading. Though it has taken the plant some 150 years, it has now been reported in 29 different states and is working its way toward you. The plant has managed this feat by being sneaky and by by being prolific. It takes a garlic mustard two years to mature; during the first year, it is a small, leafy plant that morphs into a spike of flowers and seeds in its second year. A single plant can produce nearly 8,000 sticky seeds that are carried near and far by unwitting animals, and the seeds can germinate up to five years after they ripen. And upwards of 1,800 garlic mustard plants can sprout in a single patch one square foot large!

If you’d like to help hunt down this invader (either for lunch or just because you prefer your forests without invasives), then head over to the Global Garlic Mustard Field Survey. They’ll show you how to identify garlic mustard, tell you how to combat it, and listen to your tales of the forest (especially if they feature the defeat of the evil garlic mustard).

July 2 – Is There Anybody Out There?

Today’s factismal: It is World UFO day.

There is no doubt that UFOs exist; there are objects that are flying around that are not identified. But a far more interesting question is “Are there other planets with intelligent life?” And the answer to that is still not known.

Is this your Uncle Martin? (Image courtesy Jack Chertok Television)

Is this your Uncle Martin?
(Image courtesy Jack Chertok Television)

But that doesn’t mean that we can’t try to know the answer. One of the most famous attempts to resolve the question was made by Drake, who put together an equation estimating the number of intelligent civilizations in the universe:

Number of civilizations = Galaxies * Stars * Planets * habitable * life * intelligence * civilization

In order to solve Drake’s equation, all you have to do is know how many galaxies there are and the number of stars in each galaxy and the number of planets orbiting each star, along with the fraction of those planets in the “habitable zone”, the fraction of habitable planets that go on to develop life and the fraction of planets with life that develop intelligent life and the fraction of planets with intelligent life that go on to develop civilization. Of these factors, we have a good handle on the first two, and are getting some interesting information on the next two.

Has Kreton contacted us? (Image courtesy Jerry Lewis Show)

Has Kreton contacted us?
(Image courtesy Jerry Lewis Show)

We know that there are about 500 billion galaxies in the universe (G=500,000,000,000). And we know that there are about 100 billion stars in a typical galaxy (S=100,000,000,000). Based on our observations of exoplanets, it appears that nearly every star will develop planets, so we can arbitrary put P at 0.9. Also based on our exoplanet work, we know that about 10% (h=.1) of those will be in the habitable zone; i.e., neither so close to their sun that the planet is too hot for life, nor so far out that it is too cold.

The one, true Spock (Image courtesy Paramount)

The one, true Spock
(Image courtesy Paramount)

What we don’t know yet is how inevitable life is. Some exobiologists think that life is inevitable; others think that it is exceedingly rare. If we assume that life is very rare and happens in one out of every billion habitable systems and that intelligent life is even rarer and happens once on a trillion planets with life and that civilization is inevitable, we get:

N = 500,000,000,000 * 100,000,000,000 * 0.9 * 0.1 * 0.000000001 * 0.000000000001 * 1 = 4.5

So there should be about three other civilizations out there (remember that we count as one of those 4.5). Using different values for intelligence and life give different results; reasonable values range from 2 to 20,000.

Sorry, wrong planet. (Image courtesy 20th Century Fox)

Sorry, wrong planet.
(Image courtesy 20th Century Fox)

And that leads to the Fermi Paradox: “Hey! Where is everybody?” After all, if all of these civilizations existed, then there should be some evidence of them, right? Well, maybe not. You can argue (and many have) that the ETI are there but space is so big that we haven’t had time to get their signals. You can argue (and many have) that they exist but will not communicate with us due to some “Prime Directive”. Or you can argue (and many have) that the act of communication is so fraught with assumptions that they are shouting at us, but we simply cannot understand them.

If you’d like to do more than just toss numbers at the problem, then do I have a citizen science opportunity for you! The SETILive community is gathering radio signals from stars that we know have planets in the habitable zone and they need volunteers to look at the signals to see if there’s communication buried in it. To get in on the search, set your coordinates for